MKS/HPS Vacuum Gauge Controller Device Support

Contents

• Overview
• Files
• Configuration

This module provides EPICS AI (Analog Input) device support for the HPS SensaVac Series 937 Vacuum Gauge Controller (made by MKS Instruments), using HiDEOS.

The Model 937 is capable of controlling up to 5 vacuum gauges, including cold-cathode, Pirani, capacitance manometer, thermocouple, and convection gauges. The Model 937 communicates via a serial port, which can either be single-drop RS-232 or multi-drop RS-485. This device support package presently uses only RS-232 communication. RS-485 may be added in the future.

This device support package does the following:

• On record initialization:
  • If rec.PREC=0 then it sets rec.PREC=1. PREC=1 will display the actual number of digits reported by the 937.
  • Queries the 937 to read the current gauge units (Torr, Pascal, etc.) and sets rec.EGU to this string.
  • Queries the 937 to determine the gauge type (cold-cathode, Pirani, etc.) This information is used to determine the lower and upper limits of this gauge.
  • If rec.LOPR=0 and rec.HOPR=0 sets these to the upper and lower limits of this gauge type.
• On record processing
  • Reads the current pressure from the gauge.
  • If the pressure is above or below the range of this gauge, sets a minor alarm and sets rec.VAL = minimum or maximum value for this gauge type.
  • If the gauge returns any other error or if the read request times out, then it sets a major alarm and sets rec.VAL=0.
  • If there are no errors then rec.VAL is set to the pressure and device support returns 2 to tell record support not to convert the value, since it writes directly to the VAL field.

Files to be placed in <top>/cat_ascii/
devSup.ascii	This file is not included in the distribution. However, the user must edit this file and add the following line: "ai" VME_IO "devAiMKS" "Hideos MKS"
Files to be placed in <top>/<app>App/op/adl/
DualVacuumGauge.adl	This file builds an medm screen to display a cold-cathode and Pirani gauge on a single screen. To use it from the command line, type the following: cars> medm -x -macro TITLE=my_tank, CC=my_cc, PR=my_pr DualVacuumGauge.adl where my_tank is the name of the vacuum tank, my_cc is the name of the record for the cold-cathode gauge, and my_pr is the name of the record for the Pirani gauge. This file can also be used as a related display from other medm screens by passing the arguments TITLE, CC, and PR.
DualVacuumPlot.adl	This file is called as a related display from DualVacuumPlot.adl, and displays the time-history of the vacuum gauges.
Files to be placed in <HiDEOS top>/epics_hideos/
devAiMKS.cc	This file contains the EPICS HiDEOS device support for the HPS 937 for the analog input record.
Makefile.Hideos	This file is not included in the distribution. However, the user must edit this file to add devAiMKS.cc and devAiMKS.o, similar to the following: OBJS = devHideos.o devAiTest.o histo_test.o \ devSiHideos.o devSoHideos.o devSoiHideos.o \ devAiADC.o devAiLove.o devMetasys.o string_test.o \ Gpib.o serial_config.o devAoDAC.o \ devFanuc.o devAiMKS.o SRCS = devHideos.cc devAiTest.cc histo_test.cc \ devSiHideos.cc devSoHideos.cc devSoiHideos.cc \ devAiADC.cc devAiLove.cc devMetasys.cc \ string_test.cc Gpib.cc serial_config.cc \ devAoDAC.cc devFanuc.cc devAiMKS.cc

Configuration

To configure an EPICS Analog Input record to use this device support you must select "Hideos MKS" as the INP link. The card number is 0 if using an IP slot on the vxWorks main processor, 1 for the first auxialliary MV162 in the system, etc. The PARM field is specified as follows:

x-Serial[n],m

The serial port settings must be set in the vxWorks startup file to use the correct baud rate and even parity. For example:

ConfigureHideosSerialPort("a-Serial[1]",1,19200,'E',8,1,'N')