There are essentially four commands for controlling I/O devices. Two of those commands work with keywords and two of them work directly with the specific devices' command languages (Lakeshore and/or DGH). The following is a synopsis of the commands which are discussed in detail below.

mm ch1spd=3.0       mm writes to keywords
sm ch1spdrbv        sm reads keywords
td 5 "SETP 1,14.0"  td outputs command strings to devices
ad 5 "KRDG? 1"      ad outputs command strings to devices and awaits a reply

Device, channel, and keyword designations

There are 3 Lakeshore units and 5 DGH units. The correlation between unit and device number, signals and keywords are as follows:

1  DGH 4172   is the single stage coldhead's speed control
              CH1SPD    the speed control keyword which is connected to 
                        the analog output channel 0

2  DGH 1132   is the single stage coldhead's on/off controls
              CH1PWR    the coldhead's power control which is connected 
                        to digital output signal 0  

              CHREMOTE  the remote/local control affecting all the DGH
                        units and is connected to digital output signal 1 

              CH1SPDRBV  the coldhead's current speed readback value and
                         is connected to analog input signal 0 

3  DGH 4172   is the dual stage coldhead's speed control
              CH2SPD     speed control keyword which is connected to the
                         analog output channel 0

4  DGH 1132   is the dual stage coldhead's on/off controls
              CH2PWR     coldhead's power control and is connected to
                         digital output signal 0 

              CH2SPDRBV  coldhead's current speed readback value and
                         is connected to analog input signal 0 

5  Lakeshore 340 is the temperature controller
              TEMPDET    temperature sensor at the back of the detector
                         which is the units channel 1 input

              THEAD2HI   coldhead's high stage temperature which is the
                         units channel 2 input

              DETSTPT    detector temperature setpoint (channel 1)

              OPTBSTPT   optical bench temperature setpoint (channel 2)

6  Lakeshore 218 is a temperature monitor (channels 1-8 in order below)
              TDETBLCK   detector block temperature

              TGETTER    getter temperature 
   
              THEAD2LO   dual stage coldhead's low stage temperature

              TCAMERA    camera temperature 

              TCOLL      collimator temperature  

              TBENCH     optical_bench temperature
  
              TSHIELD    shield temperature 
   
              THEAD1     single stage coldhead temperature

7  DGH 1712   is the calibration lamps' power controls (digital output 0-7)
              ARGONPWR   argon lamp's power control

              KRYPTONPWR krypton lamp's power control

              LAMPPWR    spectral lamp's power control

              NEONPWR    neon lamp's power control

              XENONPWR   xenon lamp's power control

8  Lakeshore 218 is the second temperature monitor (2 channels used)
              TM2_TEMP1  temperature input channel 1 

              TM2_TEMP2  temperature input channel 2

Reading/Writing Keywords

The commands affecting keywords are the observatory wide standard commands which allow one to read and write keyword values. The write command is modify and the read command is show.

The use of show and modify requires one to specify a service. In the case of NIRC2, example commands would be :

modify -s nirc2 optstpt=15.35 
show -s nirc2 ch1spdrbv

UNIX aliases have been created for show and modify as shortcuts, so the examples can be simplified to:

mm optstpt=15.35
sm ch1spdrbv

Reading/Writing Lakeshore and DGH Parameters

The commands for interfacing to the I/O modules are askdevice and telldevice. The aliases for these are, respectively, ad and td.

The difference between askdevice and telldevice is that askdevice waits for a response from the device and, hence, would be used for reading current device values (eg. RS, KRDG?, ...).

To use these commands one must specify a device number followed by a string comprising of a device command. One can specify multiple commands if they are all enclosed in a single set of double quotes. Be aware that:

Askdevice will only wait for a single response, so a string consisting of multiple commands should only contain a single query command.
Most Lakeshore commands must be enclosed in double quotes because they either take a parameter or contain punctuation characters which get trans- lated by the UNIX shell and are not passed through to the device.
Command strings are not parsed/inspected but are sent exactly as typed, hence, case is important.

Examples for each device follows:

ad 1 RS            returns single stage coldhead's DGH 4172's setup
td 1 AO1.0         sets the modules analog output       
ad 1 RAO           readback of the modules analog output signal

ad 2 RS            returns single stage coldhead's DGH 1132's setup
td 2 DO03          sets both digital outputs on (be vigilant here as
                   the outputs are inverted in the electronics so setting
                   the outputs on actually turns the controls off)
td 2 DOFF          ditto          

ad 3 RS            returns dual stage coldhead's DGH 4172's setup
td 3 AO3.0         sets the modules analog output
ad 3 RAO           readback of the modules analog output signal

ad 4 RS            returns the dual stage coldhead's DGH 1132's setup
td 4 DO01          sets the digital output on (off at the controls)
td 4 DOFF          ditto          

ad 5 "KRDG? 1"     returns the temp controller's temp channel 1 value
ad 5 "HTR?"        returns the controller's heater output in percent
ad 5 "FILTER? 1"   returns filter 1's input parameters
td 5 "SETP 1,30.0" sets control loop 1's setpoint

The commands to the Lakeshore temperature monitors (218) are similar but 
the valid commands are a subset of the temperature controllers.