From f63ab1ba0a3d16103fb244065d0187b34cefb90a Mon Sep 17 00:00:00 2001
From: Jack Harper <jack.harper@stfc.ac.uk>
Date: Tue, 26 May 2026 17:04:49 +0100
Subject: [PATCH] add conditional for frozen offsets for TC

---
 TC/iocBoot/iocTC-IOC-01/config.xml    | 2 ++
 TC/iocBoot/iocTC-IOC-01/st-common.lua | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/TC/iocBoot/iocTC-IOC-01/config.xml b/TC/iocBoot/iocTC-IOC-01/config.xml
index 298e7492f..4c60eb061 100644
--- a/TC/iocBoot/iocTC-IOC-01/config.xml
+++ b/TC/iocBoot/iocTC-IOC-01/config.xml
@@ -8,6 +8,8 @@
 <macro name="ADS_PORT" pattern="^[0-9]{1,5}$" description="ADS port to use for communication" hasDefault="YES" defaultValue="852"/>
 <macro name="MTRCTRL" pattern="^[0-9]{1,2}$" description="Controller number used in motor address assignment" hasDefault="NO"/>
 <macro name="PLC_VERSION" pattern="^[1]$" description="The PLC version to communicate with: 0 for the old ISIS code (now removed) and 1 for new collaboration code" defaultValue="1" hasDefault="YES" />
+<macro name="FORWARD_DESC" pattern="^1|0$" description="Whether to poll and forward axis description to .DESC" hasDefault="YES" defaultValue="0" />
+<macro name="ALLOW_FROZEN_OFFSETS" pattern="^1|0$" description="Whether to allow frozen offset behaviour" hasDefault="YES" defaultValue="0" />
 </macros>
 </config_part>
 </ioc_config>
diff --git a/TC/iocBoot/iocTC-IOC-01/st-common.lua b/TC/iocBoot/iocTC-IOC-01/st-common.lua
index de8634601..a6f03b2f5 100644
--- a/TC/iocBoot/iocTC-IOC-01/st-common.lua
+++ b/TC/iocBoot/iocTC-IOC-01/st-common.lua
@@ -10,6 +10,7 @@ function twincat_stcommon_main()
 	local plc_version = ibex_utils.getMacroValue{macro="PLC_VERSION", default="1"}
 	local ads_port = ibex_utils.getMacroValue{macro="ADS_PORT"}
 	local forward_desc = ibex_utils.getMacroValue{macro="FORWARD_DESC", default="0"}
+	local enable_frozen_offsets = ibex_utils.getMacroValue{macro="ALLOW_FROZEN_OFFSETS", default="0"}
 	asyn_port = ibex_utils.getMacroValue{macro="PORT"}
 
 	num_axes = ibex_utils.getMacroValue{macro="NUM_AXES"} -- todo: actually poll the device to get this
@@ -34,6 +35,11 @@ function twincat_stcommon_main()
 			iocsh.dbLoadRecords("$(MOTOREXT)/db/desc_tc.db", desc_tc_args)
 		end
 
+		if enable_frozen_offsets == "1" then
+			local frozen_offsets_db_args = string.format("P=%s,AXIS_NUM=%s,ADSPORT=%s,PORT=%s", ioc_prefix, axis_num, ads_port, asyn_port)
+			iocsh.dbLoadRecords("$(MOTOREXT)/db/frozen_offsets.db", frozen_offsets_db_args)
+		end
+
 		motor_pv = string.format("MTR%02i%02i", mtrctrl, axis_num)
 		single_axis_db = "$(TOP)/db/single_axis.db"
 		db_args = string.format("MYPVPREFIX=%s,MOTOR_PV=%s,MOTOR_PORT=%s,ADDR=%s", pv_prefix, motor_pv, motor_port, axis_num-1)