TPGx00

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TPGx00

TPGx00 is shorthand for the TPG300 and the TPG500 Pfeiffer Vaccuum Gauges which use the same TPG300 IOC, which controls a series of four pressure sensors (A1, A2, A3, A4).

To configure the IOC for the 500, define the MODEL macro: it defaults to TPG300

These devices are similar to the TPG26x and TPG36x, but have 4 pressure sensors to read from, and have a slightly more complicated IOC. All their manuals can be found in <share>\ISIS_Experiment_Controls\Manuals\Pfeiffer TPG<xxx>.

Differences between the 300 and 500

The TPG500 is the slightly newer version of the TPG300; the main differences between these two devices is in their communication protocols. See the manuals for what these properties are used for.

	300	500	Affected commands
Switching Functions	1, 2, 3, 4, A, B	1, 2, 3, 4	SPx
Switching Function assignments	No Assignment, A1, A2, B1, B1, A1 self-monitoring, A2 self-monitoring, B1 self-monitoring, B1 self-monitoring	Off, A1, A2, B1, B2, On	SPx
Units	mbar, Torr, Pa	hPascal, mbar, Torr, Pa, Micron, Volt, Ampere	UNI/UNIx

Some less explicit differences are as follows:

• Communication terminators
  • in the TPG300 manual, there is a mismatch of <CR><LF> and <CR> receive acknowledgement terminators. The TPG500 consistently uses <CR><LF>. This may be a typo in the TPG300 manual, but luckily as all the commands we use for the TPG300 are listed as using <CR><LF>, this shouldn't cause any headaches.
• SPS command
  • Although the 300 and 500 have a mismatch of switching functions, SPS returns status values for all switching functions (e.g. 1|2|3|4|A|B) for both models. However, we don't actually care about the return values for SFs A and B for either model, so these last two values are skipped in the protocol file. Regardless, it's worth noting that for the 500 the values returned for A and B are:
    • 1 if an automatic function is active for sensor A1 (for SF A) or B1 (for SF B) and the sensor is ON
    • 0 otherwise
• SPx command
  • This command returns a couple of parameters, one of which is the 'switching function assignment'. As noted above, these differ between the 300 and 500, but most importantly, B1 being repeated twice isn't a typo - this is specified in the manual. By contrary, the 500 does have a B2.
  • For the 500, this command returns an extra parameter which is the 'ON-Timer', but we don't care about this so is skipped in the protocol file.

Commands

The IOC currently supports the use following commands with the TPGx00 devices:

Command	Description
Pxx, where xx is A1|A2|A3|A4	Gets the pressure measurement from the specified channel
ERR	Get the error status of the device
SPS	Get the statuses of all switching functions 1|2|3|4|A|B
SPx, where x is 1|2|3|4 (+ A|B for 300)	Get/set the threshold settings for a specified switching function
UNI	Get the unit of measurement
UNIx, where x is 1|2|3 (+ 0|4|5|6 for 500)	Set the current unit of measurement

At the moment, there is some level of protection for using invalid commands between devices (e.g. sending a UNI6 to a TPG300):

• $(P)UNITS:SP (note: not $(P)UNITS) goes into alarm if set outside the states defined for the current model
• $(P)FUNCTION has protective PV $(P)FUNCTION:VALID which only allows switching function SP/RB PVs to interact with the protocol file IFF $(P)FUNCTION is in a 'valid' state.
  • For example, if you try to query the switching function B on a TPG500, SPB cannot be sent to the TPG. However, as of #7458, no alarm is raised if $(P)FUNCTION is set to B, as is with :UNITS:SP.