diff --git a/VAX/vax730_stddev.c b/VAX/vax730_stddev.c
index b12f59fa..cf810dc5 100644
--- a/VAX/vax730_stddev.c
+++ b/VAX/vax730_stddev.c
@@ -762,7 +762,7 @@ void tmr_sched (uint32 nicr)
 {
 uint32 usecs = (nicr) ? (~nicr + 1) : 0xFFFFFFFF;
 
-clk_tps = 1000000 / usecs;
+clk_tps = (int32)((1000000.0 / usecs) + 0.5);
 
 sim_debug (TMR_DB_SCHED, &tmr_dev, "tmr_sched(nicr=0x%08X-usecs=0x%08X) - tps=%d\n", nicr, usecs, clk_tps);
 tmr_poll = sim_rtcn_calb (clk_tps, TMR_CLK);
diff --git a/VAX/vax750_stddev.c b/VAX/vax750_stddev.c
index 799765bb..d5715e08 100644
--- a/VAX/vax750_stddev.c
+++ b/VAX/vax750_stddev.c
@@ -758,7 +758,7 @@ void tmr_sched (uint32 nicr)
 {
 uint32 usecs = (nicr) ? (~nicr + 1) : 0xFFFFFFFF;
 
-clk_tps = 1000000 / usecs;
+clk_tps = (int32)((1000000.0 / usecs) + 0.5);
 
 sim_debug (TMR_DB_SCHED, &tmr_dev, "tmr_sched(nicr=0x%08X-usecs=0x%08X) - tps=%d\n", nicr, usecs, clk_tps);
 tmr_poll = sim_rtcn_calb (clk_tps, TMR_CLK);
diff --git a/VAX/vax780_stddev.c b/VAX/vax780_stddev.c
index c610ef7d..6bcc759d 100644
--- a/VAX/vax780_stddev.c
+++ b/VAX/vax780_stddev.c
@@ -728,7 +728,7 @@ void tmr_sched (uint32 nicr)
 {
 uint32 usecs = (nicr) ? (~nicr + 1) : 0xFFFFFFFF;
 
-clk_tps = 1000000 / usecs;
+clk_tps = (int32)((1000000.0 / usecs) + 0.5);
 
 sim_debug (TMR_DB_SCHED, &tmr_dev, "tmr_sched(nicr=0x%08X-usecs=0x%08X) - tps=%d\n", nicr, usecs, clk_tps);
 tmr_poll = sim_rtcn_calb (clk_tps, TMR_CLK);
diff --git a/VAX/vax860_stddev.c b/VAX/vax860_stddev.c
index 7627c7cb..93c6345c 100644
--- a/VAX/vax860_stddev.c
+++ b/VAX/vax860_stddev.c
@@ -863,7 +863,7 @@ void tmr_sched (uint32 nicr)
 {
 uint32 usecs = (nicr) ? (~nicr + 1) : 0xFFFFFFFF;
 
-clk_tps = 1000000 / usecs;
+clk_tps = (int32)((1000000.0 / usecs) + 0.5);
 
 sim_debug (TMR_DB_SCHED, &tmr_dev, "tmr_sched(nicr=0x%08X-usecs=0x%08X) - tps=%d\n", nicr, usecs, clk_tps);
 tmr_poll = sim_rtcn_calb (clk_tps, TMR_CLK);