Agilent (formerly HP, now Keysight) vs Tektronix

I am much more inclined towards Agilent than Tektronix because

  • There’s nothing a Tek scope can do that an Agilent can’t
  • Agilent’s user interface is very intuitive that it requires little to no trial-and-error or RTFM.
  • Agilent’s people are often very generous about helping customers out even if support is discontinued. Tek gets rid of all service information and software after discontinuation by policy.
  • Agilent’s gears are very thoughtfully designed and is a pleasure to service, for the ones that I have opened up so far. Tek designed their unit to live barely enough through their support lifecycle, hoping they won’t have to service it.
  • Agilent’s old gears lives much longer. Just look at (even better, open up) Agilent 54600 series and the damn TDS 300~800 series and you’ll see what a nightmare Tek is.
  • Tek’s autoscale algorithm is a piece of garbage!
    Even with TDS6000B/C series that cost tens of thousand of dollars at the time of writing still couldn’t figure out the top Ghz signals and give you a long Time/Div that completely aliases the signal and therefore confuse the heck out of their users. Not to mention Tek’s autoscale is sometimes too dumb to figure out which one channel you are on so that you have to move to (highlight/focus on) the right channel. Never had to deal with this kind of nonsense while using an Agilent scope.
  • Agilent’s gears also have much fewer hard/painful to fix aging problem than Tek.
  • When Tek scope fails, it’s often followed by a bunch of other unrelated aging problems. The capacitors are not designed to stand the heat for 10 years of usage.

EDIT: It’s not just me bitching about how unresponsive the controls (especially the dials) are in their user interface. Dave Jones did a video review of MDO4000 and a bunch of people share the same frustration in the comments section. I thought they improved after TDS1002B (I stopped following their newer scopes), but I was wrong. Still the same poorly thought-out and laggy UI.

There is Lecroy, but there are much fewer old gears in circulation and I don’t like their user interface much either, but at least the dials won’t take more than half a second to respond like Tek. I once asked Lecroy if they can generously share the schematic for an old unit like Agilent and they sent me one. At least they are not being a d**k about it like Tek.

I have both used Agilent and Tek scopes for sale, but my own bench is all Agilent whenever there’s a choice. Tek is OK if you plan out a difficult measurement setup (for documentation or manufacturing), but miserable if you are poking around to troubleshoot (that’s what I use the gears for). I sell Tek just to cater those who have been brainwashed because Tek got the first-mover advantage back in the days.

Of course my bias is based on their Tek’s gears in the digital age. I heard that they were very good at the analog scope times, so that might be the reason why Tek still has a strong following. HP/Agilent/Keysight pretty much nailed the digital techniques. The part I liked about Agilent is that they are generous about making users of their products happy in general, regardless of whether you recently paid them or not. For deeply discontinued products (like 3+ generations ago), they are happy to pass whatever information they have left to help DIY-ers or non-chartered 3rd parties that are willing to service them (like this one, which people are asking for recovery discs for their 1680 series analyzer and the staff went all the way to dig it up from their private stash!) so the company can focus on the newer products.

Support culture aside, Tek’s used gears are so problematic (I learned it first-hand, the hard way) that I’m now hesitant about buying them as investments. It looked like an opportunity because Tek stuff often breaks the same way, so I can buy them cheap, fix them, and resell. But the reality is that the labor is simply not worth it because it’s often not just one problem, but one quickly after another. Now I’m just selling whatever Tek leftovers I have strengthened in the past.

You might think Agilent is sabotaging their own market by taking care of users of their old gears. It isn’t. Whoever that has the budget to buy new will do so. Wobblers between buying new/old gears are not worth agonizing over. The ones who are familiar with the older gears will grow fond of the brand and the user interface/environment they are familiar with and will push their employers to buy Agilent when they get a chance to buy it new. I used to have a customer that I convinced them to get a used Agilent one instead of used Tek, and they ended up loving it so much that they bought a new one from Agilent for their second scope. What goes around, comes around.

I realized throughout the years is that whatever hobbyists do with the old gears and can only help the brand image and build a stronger user base. It’s the user base (engineer’s familiarly) that makes or breaks the deal on new gear purchase. I don’t think big companies that pays good money to buy new will switch to all Tek from Agilent all of a sudden when all engineers are comfortable with Agilent’s stuff, and vice versa.

Loading

Oscilloscope Probing – Bob Pease Show

Once in a while customers ask me about what probes do they need to go with their high bandwidth oscilloscopes.

Agilent already has application notes about how to probe properly at high frequencies to ensure what you see on the scope represents the reality faithfully, but they are a little dry. Bob Pease Show at National Semiconductor (now acquired by Texas Instruments) talked about it and it’s great infotainment due to Bob Pease’s character:

This show has significant product placement by Tektronix, but the information there applies equally (and fungibly) to all major name brands such as Agilent/HP/Keysight and Lecroy. They all live up to the specs advertised.

What I’ve learned from the video

  • No-name brand probes might not live up to the claimed specs. I wouldn’t trust a Chinese probe beyond 100Mhz (or even 60Mhz).
  • Shorten the ground leads as much as possible, especially high frequencies. Wires are inductors/antennas.
  • Do not use the poor-man’s differential probes (aka subtracting the channels on the scopes): the channels aren’t matched perfectly, the probes aren’t matched perfectly either.
  • Design for testing: plan your PCB so you can probe easily.
  • For digital designs, high bandwidth scope users care more about (time-domain) step response: rise-time, ringing, settling, than it’s frequency domain (I don’t have a fast pulse generator, this is why I test it with a RF generator to check the specs)
  • Active probes have less loading and attenuation. You can use passive probes if you have a large enough signal to burn.
  • Probe capacitance (loading) kills a fast circuit (by damping it down)
  • Don’t be happy because you see nice waveforms and nothing bad happens with a low bandwidth scope+probe: you are just failing the capture transients.

Loading

Quick setup guide for Agilent E2050A GPIB Gateway

For the convenience of my customers, I compiled a quickie setup guide so they don’t have the RTFM.

E2050A does not have DHCP. Most likely your network doesn’t have a ancient BOOTP server, so it means you are better off letting E2050A have a static IP address.

The big idea is that you’ll first need to talk to the E2050A, and the only way it can happen is that the computer talking to it has to be on the same subnet (and the corresponding IP address range). Doesn’t matter how you achieve it as long as you keep this in mind. Once you gained access to the router (telnet config screen), you can change the network setting of the E2050A to match whatever network you want to put it on later.

If you don’t know the E2050A’s network configuration, reset it to the default so you have a deterministic starting point and follow the instructions below:

  1. Reset the instrument to factory state by holding down CONFIG PRESET switch while applying power, because you want to know the IP address for sure so you can get into the instrument.
  2. The default static IP address is 192.0.0.192, under subnet mask 255.255.255.0
  3. Most likely your internal network is not 192.0.0.XXX, so you might want to use a computer with a network card (NIC) to talk to the device directly* (point-to-point) first so you can gain entry to the E2050A and change its network configuration.
  4. The NIC on the computer talking to the E2050A must be set to an IP address in the same subnet. This means only the last (rightmost) group of the NIC’s static IP address can be different. An example for the computer’s NIC static IP setting: 192.0.0.190 with subnet 255.255.255.0.
  5. Now you can talk to the E2050A directly by addressing 192.0.0.190. If it’s a dedicated computer for an automation set and you don’t want it to talk to the rest of the network, you are done.

I made up 192.0.0.190. Anything from 192.0.0.1 to 192.0.0.254 works. Thou shalt not use 192.0.0.0 (for it is the network identifier) or 192.0.0.255 (for it is the network broadcast address) or 192.0.0.192 (as it conflicts with the E2050A’s IP).

Most likely you will want to put the E2050A on your home/business network for convenience, unless you want to eliminate network security issues. Then you’ll need to follow a few more steps:

  1. Telnet to the E2050A at 192.0.0.192 to change its static IP address and subnet to fit your network. After saving and rebooting, you must address it with the new IP address you assigned (obviously!).
  2. Note that the default (SICL) interface name on the E2050A is “hpib”, which is different from E5810A’s default “gpib0”. Either change it on the E2050A (it’s called “hpib-name”) or enter the “hpib” for interface name on Agilent’s I/O suite.
  3. You can leave the rest of the settings alone in Agilent I/O suite if you want to simply talk (in its raw, instrument-specific GPIB commands) to the unit without using VISA or SICL layers (standardized syntax).

E2050A has the same software communication interface as E5810A, so you can just select E5810A as the remote interface for the E2050A and remember to enter the correct interface name as discussed above.

Note that E2050A does not work properly (won’t detect) on the redesigned Keysight-branded I/O Suite until version 2019. Please either use version 2019 and after OR the older Agilent branded I/O Suite.

I have E2050A as well as E5810A for sale. Please contact me from my business website (www.humgar.com) or my phone 949-682-8145.


* Unless you are using a very ancient computer, the NIC can auto-negotiate direct connection that you can simply use any regular old straight RJ-45 cable. If you have a really old computer, you’ll need a cross-over cable to do point-to-point ethernet.

Loading

GPIB to Ethernet Gateway (Agilent E2050A or E5810A, NI, Tek, ICS) Don't bother with USB-GPIB adapters. Ethernet-GPIB gateways are cheaper and better.

GPIB gateway is a device that allows you to remotely control / talk-to test instruments (as well as ancient printers/plotters, etc) that uses the most popular protocol. It’s so popular and timeless that even new test instrument finds a way to support it. This protocol just wouldn’t die.

The major downside of USB-GPIB interfaces (cheaper) is that it requires driver support, which is OS dependent. Keysight can choose to drop support at anytime. You can always fire up a virtual machine to use old software talking to a hardware using TCP/IP, but not reliably with USB (sometimes you get glitches and timing issues with virtual machines especially when it streams live data even at kHz range).

It’s usually a good idea to stick with GPIB if you have an automation setup that involves at least ONE piece of test instrument on GPIB. A ethernet port (LXI) on a modern test gear is fine, but you don’t really want to complicate your code managing network connectivity checks for each IP-based instrument and make sure they work together. With GPIB, you can chain 14 instruments with one gateway so you don’t have to worry about network problems if you can connect to any one of the device on the chain.

Here’s a nice GPIB tutorial document if you’d like to get into the nitty-gritty:
http://www.essproducts.com/wp-content/uploads/2015/06/ab48_11.pdf


E2050A is my favorite GPIB gateway due to its compact size. It’s good enough for most purposes, since I don’t really have any instruments that need or support the extra speed from 488.2. The biggest annoyance is that E2050A does not have DHCP, but uses an an ancient BOOTP instead. This means for modern networks, you might as well give it a static IP.

E5810A is the newer revision of E2050A, with the same internal interfaces. That means all software, including Agilent I/O Suite, fully supports E2050A as a E5810A. E5810A comes with a few minor improvements

  • it adds a web interface (not very useful other than upgrading firmware)
  • supports 488.2, which means 9x faster GPIB communication if the instrument supports it
  • DHCP: automatically acquiring IP address

Unfortunately, E5810A is a bigger unit, partly because the power supply is built-in, and it comes with a LCD screen. Nonetheless, I opened up a E5810A and the inside has a lot of empty spaces.

Telnet is supported for both E5810A and E2050A. For E2050A, telnet is the only way you can get inside the unit and change the configuration such as IP address and interface name. Telnet is pretty easy to use, just get the free, open-source Putty if your Windows does not come with command line telnet anymore.


There’s a E5810B, but in my opinion, it’s pointless because all it adds is a USB-over-IP interface and a front switch. This is something most ASUS routers (especially Merlin firmware) has it out of the box or there are some cheap old USB-over-IP modules (<$50) for it.  Basically if you are considering a E2050/E5810, your eyes are on the GPIB instrument base, not the USB instruments that you can put on the network with low cost USB-over-IP. It’s just fluff for Agilent/Keysight to discontinue support for the earlier models to price differentiate from the units circulating in the used market.


I’ve tried other gateways such as NI and Tektronix. There are not many NI gateways floating around and I’ve only encountered even fewer Tek gateways. Unless you have poorly written software that hard-codes to NI or Tek stack, I wouldn’t even bother installing NI/Tek GPIB stack as it can confuse some poorly designed software if the 3 stacks are not configured properly to work together peacefully. Just stick with the GPIB stack from the brand that you can easily get used units for cheap.

Be very careful about NI GPIB-ENET: it does not support anything after Windows XP at all, and there’s no way NI will bother to go back and fix it. For this I wouldn’t even want to touch any GPIB gateways done by NI since they are not as thoughtful about backward compatibility compared to HP/Agilent/Keysight.

ICS was popular a while ago making cheap GPIB controllers/converters. However, they don’t work with Agilent’s I/O suite or NI/Tek stack directly, so you are stuck with using it like a serial port. Given that the price of a used HP/Agilent’s GPIB gateway is cheaper than a new ICS gizmo, there’s no point getting ICS stuff anymore.


I have E2050A as well as E5810A for sale. Please contact me from my business website (www.humgar.com) or my phone 949-682-8145.

Loading