Roger,

The analogue output on the DT 800.... how do you control it? Is it possible to perform an operation like: "If the current at channel 1 falls below (say) 12.5mA then increase the analog output current by 10%" (For current read voltage, I would be able to work with either one.)

Good morning Frankwin,

The command to use is VO where the output value is in mV (VO=1000 will output 1 VDC) You will need to use the "User" Channel type to be able to access it.

You can assign the value of a CV to the voltage out as well, (VO=1CV)

When I find some free time I'll do a tech note on PID closed loop control.

Cheers,
Roger

In addition to this I would like to know why the output drops from 10 Volts to 0 Volts in a few seconds after VO=10000 is given. And if I repeat the commando the output doesn't do anything anymore unless I reset the output first back to 0V with VO=0

Another question in relation to this is that I need 2 more digital output channels than are available on D1..D8. Therefore I thought that it should be possible to use either A0 or the Serial output "12V" or serial output "RT" signals. I need the extra outputs to give a pulse to a water sampler during at least 25 ms in a voltage range of 5 - 15 volts. What is wise?

Regards,
Gerben

Good morning Bakker,

1. Analog output.
   What version of firmware is the DT800 running?

2. Extra digital outputs.
   We would not recommend using the analog output as you will break the isolation between the analog and digital systems which could use more problems. Have you though about using an external circuit to increase the digital channels? Using byte addressing you can in have up to 256 digital.

Cheers,
Roger

Good morning Roger,

1. Analog output: the firmware version is displayed as: 4.10000. It was upgraded a few days ago when I installed the download version of Delogger (Delogger 4, version 3 rel.4)

2. Extra digital outputs.
   An external circuit may be possible, but I don't see any proceedings in the manual according to that issue and on the other hand I'd rather keep it as simple as possible. Using an external relays should overcome your problem, am I right? And how about the Serial output "12V" or serial output "RT" signals?

Gerben

Good morning Bakker,

1. Analog output.
   I have been testing the analog output and there is no delay between sending the command and the voltage changing. What are you trying to drive? The analog output can only drive a maximum of 20 mA. If you device needs more then you will need to connect an amplifier.

2. Extra digital.
   We recommend you use an external circuit but if you want to try then that's up to you.

Cheers,
Roger